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Old 03-01-2010, 04:29 AM
RICK LAKE RICK LAKE is offline
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Location: E BRUNSWICK N.J. USA,
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RodKnock A bronze gear is designed to wear out on a roller camshaft DEPENDING on a couple of things
#1 endplay on the distributor shaft
#2 what oilpump you are running and if it's a HP or HV or both. Standard pump is the easies to drive unless its blue printed, coated and the gears ride on bearings. There are also 2 different types of pumps Geo gear pump and straight gear pump. I have not seen a test on which one causes less wear and stress on the distributor gear and shaft.
#3 End play of the camshaft will prewear out the distributor gear if to much
#4 No oil in the gear to gear contact location Dry on Dry. Some motors have an oil sparyer setup to help this, and not rely on splash or mist in the block.
#5 The hole in the motor block being centered to the camshaft bore, this helps keep everything at a 90 degree angle or a little less because of drive rotation. Some guys also use a bearing here for the distributor to ride on.
#6 Spring pressures and camshaft profile on the lift also help increase wear.
Rod as far as the poly gear I have, it's only got about 30 hours of motor race time on it and I have added oiling to this location to help control wear on the gear. I also have to be careful with leeting the motor warn up on it's own before doing any thing. Cold pressure on a hot track day is in the 110-120 psi on startup. It gets to 130 on cooler days. I am pushing that gear hard. So far there is no wear on the gear. You can just start to see a little( and I mean little contact point) on the gear. This is with a crane hydro roller camshaft. I do limit my motor to 6,200 rpms also Max is 6,500 rpm. IMO these are the max long term rpms for longer life of any motor but an overhead cam one. I don't know how long this gear will last, but have done everything I can to extend the life of this part except for the torington bearing for it to ride on.
I have one suggestion, I you have MSD igntion system in the car, BUY a complete spare setup and carry it with you in a bag and the basic tools you need to repair it. Mostly I see the carbon center burn or fall out of the cap. Sometimes see a hole in the center of the rotor. All this is easy to fix on the side of the road. once the motor cools off. Hand soap or gloves also throw into the bag. Just remember where the rotor was pointing and the housing was positioned. It will not be perfect but will get you home instead of on the hook or rollback. I have seen a few frontends get chewwed up from being put on roll backs. Rod on a side note, I think you need to stop getting crazy over how many miles the motor lasts without being rebuilt. It's 90% on how you drive and abuse the car, just like the brakes,tires, and clutch. All wear out items to protect the most expensive parts. Motor, trans, rearend, and your wallet.
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